The 500-megawatt Palen solar project would be built near Desert Center, between Interstate 10 and Joshua Tree National Park. It would join the nearby Desert Sunlight facility — which at 550 megawatts was the world's largest solar farm when it opened — and three projects near the Arizona border, known as Blythe, McCoy and Genesis.

Solar panels tilt upward to track the sun's movement through the sky at NextEra's 250-megawatt ...more

Solar panels tilt upward to track the sun's movement through the sky at NextEra's 250-megawatt McCoy solar project in eastern Riverside County on Nov. 10, 2016.

Jay Calderon/The Desert Sun

Palen's developer, San Diego-based EDF Renewable Energy, has signed a contract to sell the electricity the plant would generate to the region's major utility, Southern California Edison — a key step before construction can begin. The California Public Utilities Commission is likely to approve that contract later this month. The developer must also wait for Riverside County and the federal Bureau of Land Management to conduct an environmental review, which the agencies expect to finish later this year.

Like many solar plants in the desert, Palen has faced pushback from conservationists and tribal groups, who say the industrial facility would harm fragile ecosystems, destroy Native American artifacts and negatively impact Joshua Tree National Park, which is just eight miles from the project site. Critics have argued Palen would disrupt sand transport habitat critical to Mojave fringe-toed lizards and a corridor used by Agassiz’s desert tortoise, which is considered “threatened” under the federal Endangered Species Act.

Palen would be located within a 148,000-acre renewable energy zone designated by the Obama administration last year. But David Lamfrom, from the nonprofit National Parks Conservation Association, said it was never the government's intention for every acre to get developed. Ecosystem impacts still need to be taken into account, he said.

"You have some really unique habitat in that Palen system, including the sand dune system, and connectivity and proximity to wilderness and the national park," he said. "There’s likely less harmful locations even within that (renewable energy) zone that are currently available, and where they would run into less conflicts."

Several factors make Palen attractive to a utility like Edison, said Ian Black, the EDF executive responsible for the firm's California solar portfolio. For one thing, the desert's strong sunlight means EDF can sell the electricity at a relatively low price and still turn a profit. Palen will also be built along the I-10 corridor, where there are transmission lines ready to carry the clean power to the Los Angeles basin.

Edison has agreed to buy 125 megawatts of power from Palen, with an expected output of 406 gigawatt-hours — enough electricity to power 60,000 average California homes. EDF hopes to build out to 500 megawatts eventually, but it could start construction with just the single contract in place. The full project would span 4,200 acres of federal lands.

EDF also secured a power purchase contract last year for its 150-megawatt Desert Harvest project, which was approved in 2013 and would be built near Palen. Black wouldn't say when construction on that project will begin, but indicated Desert Harvest and Palen could be built at the same time, depending on when Palen gets its permits.

"Obviously we would want to make a plan to construct both on a timely basis, to maximize the number of local jobs and minimize the adverse impacts," he said.

EDF acquired the project from the Spanish firm Abengoa Solar last year, and quickly announced its intention to switch from the mirror-based solar technology favored by previous developers to traditional solar photovoltaic panels.

A 459-foot tall solar tower, surrounded by thousands of reflecting mirrors, at Ivanpah solar project in east San Bernardino County.

Desert Sun file

As part of their environmental review process, the Bureau of Land Management and Riverside County are considering several alternatives to EDF's proposal, including a smaller project that would span just 1,620 acres and avoid desert washes, riparian habitat and sand accumulations suitable for Mojave fringe-toed lizards. That configuration would also cut the project's power potential in half, to just 230 megawatts.

Avoiding those habitat types would follow the rules laid out in the Desert Renewable Energy Conservation Plan, an Obama administration road map for protecting California desert ecosystems while encouraging climate-friendly energy development. The sweeping land-use plan set aside 6.5 million acres for conservation and 3.6 million acres for recreation, while designating 388,000 acres for solar, wind and geothermal projects.

Conservationists have generally said the plan strikes a good balance between desert protection and energy development, but solar and wind companies have argued it closes far too much land to energy projects. Industry critics have also described certain building requirements designed to protect birds and other animals as expensive and unnecessary, saying they'll raise the cost of construction and scare away developers.

Palen was proposed before the Obama-era plan was finalized in 2016, meaning it isn't subject to those building requirements. Still, officials say the're considering the scaled-down alternative to see what it would take for Palen to comply with those rules.

Only one new solar farm has been proposed in the California desert since the Obama plan was finalized — a 200-megawatt project near Desert Center proposed by Fotowatio Renewable Ventures, which is based in Spain. No new wind farms have been proposed, seeming to validate the industry's criticism that the plan closes most of the state's best remaining wind hot spots to development. Officials marked many of those areas as off limits to prevent bird deaths and to avoid conflicts with military testing and training.

There are several other solar proposals in various stages of development in Riverside County, all of which predate the Obama administration plan. SunPower has proposed a 400-megawatt solar farm called Arica, which would be built on 4,000 acres of public land near Desert Center. Recurrent Energy is developing the 350-megawatt Crimson project, which could include energy storage, on 2,900 acres of public land near Blythe. And federal officials are working an environmental analysis of First Solar's proposed 4,800-acre, 300-megawatt Desert Quartzite solar plant on public land near the Arizona border.